1. Technical Field
The present invention is related to preparing toxoid. More particularly, the present invention is related to a novel method for chemical inactivation of toxin, particularly with H.sub.2 O.sub.2 and preparation of an acellular, detoxified vaccine therefrom.
2. State of the Art
Whooping cough (pertussis) is an infectious disease caused by the organism Bordetella pertussis. The incidence of this disease can be effectively controlled by immunization. At present national and world health organizations recommend that infants be immunized to prevent the incidence and spread of pertussis.
Three types of vaccines have been used for immunization against Bordetella pertussis. The most widely used vaccine consists of whole Bordetella pertussis organisms which are no longer viable. This vaccine, while effective in preventing disease, has several problems associated with it: (1) Administration leads to local erythema, (2) Use has been associated with induction of elevated temperature, general fretfullness and malaise, and (3) In certain instances it has been contended that administration can lead to severe neurologic sequella. In another vaccine, the pertussis component was prepared as a urea extract. This product was in use from about 1969 to 1974 but has now been withdrawn from the market. In Japan a new pertussis vaccine is in use prepared from culture supernatants of Bordetella pertussis. This material contains all culture supernatant proteins and because of variabilities in cultivation of the organism final composition can vary. In addition, use of gluteraldehyde or formaldehyde as inactivating agents can sometimes lead to aggregated materials that are subject to reversion to active toxin. It is believed that these aldehydes cause the formation of Schiff bases which are chemically unstable and thus render the toxoids subject to reversion to active toxin. Preparations of other toxins such as tetanus, diptheria and cholera toxins by hitherto known methods suffer from similar drawbacks. Hence, the need for an improved method of preparing safe and stable acellular toxins substantially free of undesirable components and effects is quite apparent.